1. Field of the Invention
The present invention relates generally to optical telecommunication, and particularly to all-optical header processing and packet switching.
2. Background of the Invention
With the increasing popularity of the World Wide Web, the Internet protocol which is by nature a packet-switching technology has become the de facto data transmission standard. However, current optical networks are still based on circuit-switching technology and therefore may not be suitable for handling heavy data traffic. Processing and routing of packet-formatted signals optically are hampered by the lack of practical optical buffers and the limited capability of available optical logic gates.
In the conventional design, a typical packet switch generally includes a header processing unit (HPU) and a packet routing unit (PRU). The HPU processes the header of an incoming packet, determines which output port the input packet should be sent, and set the PRU accordingly. During the packet transmission, either physical or logical, a data path is then provided by the PRU between the related input and output ports. Most of the current optical packet switches are in fact hybrid optical packet switches, i.e., while the packet remains in the optical domain, a copy of the packet header is converted into electrical signals for processing in the HPU. The decision of the HPU is then used to set the PRU to route the packet.